3x-15=9 ? please help?

2007-12-21 6:36 pm

回答 (9)

2007-12-21 6:53 pm
✔ 最佳答案
3x = 24
x = 8
2007-12-21 6:39 pm
3x-15=9
3x= 9+15
3x=24
x=24/3
x=8
2007-12-21 6:40 pm
3x = 15+9
3x = 24
x = 24/3
x = 8
2007-12-21 6:39 pm
3x - 15 = 9
3x = 24
x = 8
2007-12-21 8:38 pm
3x-15=9
3x-15+15=9+15
3x=24
x=8
2007-12-21 7:04 pm
3x-15=9
3x=15+9
3x=24
24/3
x=8
2007-12-21 7:03 pm
3x - 15 = 9
3x - 15 + 15 = 9 + 15
3x = 24
3x / 3 = 24 / 3
x = 8
2007-12-21 7:02 pm
All of the answers given are correct, but do you understand why? No offense intended toward the people nice enough to offer assistance, but it's important to know how to work these algebra problems and not just get the answer.

Simple strategy - The "=" is the dividing line in the equation. Whatever you do to one side, do the same thing to the other side. That's the only way to make sure things are really kept equal.

All you have to to is get the variable (x) as the only thing on one side of the "=". That's just a matter of manipulating the equation.

Given: 3x-15=9
We can start by adding 15 to each side:
3x-15+15=9+15
To simplify,
3x+0=24, or more simply, 3x=24
To get the x alone, divide both sides by 3:
(3x)/3=24/3
x=8

I noticed you posted several other algebra problems. I hope this helps with solving the others!
2007-12-21 6:58 pm
3x - 15 = 9
3x = 24
x = 24/3
x = 8


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